Component

Kynurenic acid

Independently recorded entity or measured process. Linked claims specify compartment, assay and experimental scope.

11 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What it acts on

  1. Mouse hippocampal alpha7 currents remained insensitive to kynurenic acid, including slices prepared and stored in 1 mM for over 90 minutes, although glutamatergic currents were blocked.

    Kynurenic acid → Mouse alpha7-containing nicotinic acetylcholine receptors source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Mouse hilar and stratum-radiatum interneuron recordings.
    limitations
    Does not mean kynurenic acid has no neural effects.
    nutrient_topic
    Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Tryptophan
    plain_language
    The negative receptor result persisted with prolonged high exposure and a positive pharmacological control.
    primary_references
    Lack of modulation of nicotinic acetylcholine alpha-7 receptor currents by kynurenic acid in adult hippocampal interneurons. · 2012 · https://pubmed.ncbi.nlm.nih.gov/22848433/ · DOI 10.1371/journal.pone.0041108

    Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19) · lines 306–312

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Mouse hilar and stratum-radiatum interneuron recordings. · source_derived_draft · unverified_draft

    ## tryptophan-kyna-alpha7-mouse-null The negative receptor result persisted with prolonged high exposure and a positive pharmacological control. Mouse hippocampal alpha7 currents remained insensitive to kynurenic acid, including slices prepared and stored in 1 mM for over 90 minutes, although glutamatergic currents were blocked. Model: Mouse hilar and stratum-radiatum interneuron recordings. Limitations: Does not mean kynurenic acid has no neural effects. Evidence access: Primary abstract Lack of modulation of nicotinic acetylcholine alpha-7 receptor currents by kynurenic acid in adult hippocampal interneurons. · 2012 · https://pubmed.ncbi.nlm.nih.gov/22848433/ · DOI 10.1371/journal.pone.0041108
    Complete structured claim and evidence

  2. Kynurenic acid inhibited alpha7 nicotinic responses in cultured rat hippocampal neurons after at least four minutes, with an IC50 near 7 micromolar.

    Kynurenic acid → Rat alpha7-containing nicotinic acetylcholine receptors source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Rat hippocampal culture and slice electrophysiology.
    limitations
    Direct alpha7 inhibition is disputed by a later slice study; retain assay context rather than treating it as universal.
    nutrient_topic
    Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Tryptophan
    plain_language
    One laboratory reported suppression of an acetylcholine receptor.
    primary_references
    The brain metabolite kynurenic acid inhibits alpha7 nicotinic receptor activity and increases non-alpha7 nicotinic receptor expression: physiopathological implications. · 2001 · https://pubmed.ncbi.nlm.nih.gov/11567036/ · DOI 10.1523/JNEUROSCI.21-19-07463.2001

    Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19) · lines 290–296

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Rat hippocampal culture and slice electrophysiology. · source_derived_draft · unverified_draft

    ## tryptophan-kyna-alpha7-positive One laboratory reported suppression of an acetylcholine receptor. Kynurenic acid inhibited alpha7 nicotinic responses in cultured rat hippocampal neurons after at least four minutes, with an IC50 near 7 micromolar. Model: Rat hippocampal culture and slice electrophysiology. Limitations: Direct alpha7 inhibition is disputed by a later slice study; retain assay context rather than treating it as universal. Evidence access: Primary abstract The brain metabolite kynurenic acid inhibits alpha7 nicotinic receptor activity and increases non-alpha7 nicotinic receptor expression: physiopathological implications. · 2001 · https://pubmed.ncbi.nlm.nih.gov/11567036/ · DOI 10.1523/JNEUROSCI.21-19-07463.2001
    Complete structured claim and evidence

  3. Kynurenic acid did not inhibit choline-evoked alpha7 currents in rat hippocampal slice interneurons, contrasting with earlier reports.

    Kynurenic acid → Rat alpha7-containing nicotinic acetylcholine receptors source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Adolescent rat stratum-radiatum interneurons in acute slices.
    limitations
    Slice age, temperature, agonist delivery and receptor environment are candidate explanations, not a demonstrated resolution.
    nutrient_topic
    Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Tryptophan
    plain_language
    Another experiment did not reproduce the claimed receptor block.
    primary_references
    Lack of modulation of nicotinic acetylcholine alpha-7 receptor currents by kynurenic acid in adult hippocampal interneurons. · 2012 · https://pubmed.ncbi.nlm.nih.gov/22848433/ · DOI 10.1371/journal.pone.0041108

    Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19) · lines 298–304

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Adolescent rat stratum-radiatum interneurons in acute slices. · source_derived_draft · unverified_draft

    ## tryptophan-kyna-alpha7-rat-null Another experiment did not reproduce the claimed receptor block. Kynurenic acid did not inhibit choline-evoked alpha7 currents in rat hippocampal slice interneurons, contrasting with earlier reports. Model: Adolescent rat stratum-radiatum interneurons in acute slices. Limitations: Slice age, temperature, agonist delivery and receptor environment are candidate explanations, not a demonstrated resolution. Evidence access: Primary abstract Lack of modulation of nicotinic acetylcholine alpha-7 receptor currents by kynurenic acid in adult hippocampal interneurons. · 2012 · https://pubmed.ncbi.nlm.nih.gov/22848433/ · DOI 10.1371/journal.pone.0041108
    Complete structured claim and evidence

What acts on it

  1. Human KAT-II transaminates kynurenine to an intermediate that leads to kynurenic acid.

    AADAT / KAT II → Kynurenic acid source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Human enzyme structural study and catalytic characterization.
    limitations
    The enzyme performs transamination; it does not directly perform every subsequent chemical rearrangement.
    nutrient_topic
    Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Tryptophan
    plain_language
    Kynurenine can be diverted into a neuroactive branch.
    primary_references
    Structure of the PLP-Form of the Human Kynurenine Aminotransferase II in a Novel Spacegroup at 1.83 Å Resolution. · 2016 · https://pubmed.ncbi.nlm.nih.gov/27023527/ · DOI 10.3390/ijms17040446

    Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19) · lines 210–216

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human enzyme structural study and catalytic characterization. · source_derived_draft · unverified_draft

    ## tryptophan-kat2-kyna Kynurenine can be diverted into a neuroactive branch. Human KAT-II transaminates kynurenine to an intermediate that leads to kynurenic acid. Model: Human enzyme structural study and catalytic characterization. Limitations: The enzyme performs transamination; it does not directly perform every subsequent chemical rearrangement. Evidence access: Primary abstract Structure of the PLP-Form of the Human Kynurenine Aminotransferase II in a Novel Spacegroup at 1.83 Å Resolution. · 2016 · https://pubmed.ncbi.nlm.nih.gov/27023527/ · DOI 10.3390/ijms17040446
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. 3-Hydroxykynurenine increased 39% fasting and 34% after meals; kynurenic acid decreased 22% and 20%, respectively.

    Vitamin B6 → 3-Hydroxy-L-kynurenine source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    B6-dependent kynurenine reactions intersect the tryptophan-to-niacin network; conversion to NAD was not measured.
    experimental_model
    Twenty-three healthy adults; paired pre/postprandial LC-MS/MS metabolite profiling.
    exposure
    28 days below 0.35 mg/day B6. Related restriction research program; do not count paper totals as independent trial replications.
    limitations
    Does not measure brain neurotransmitters, tissue NAD synthesis or diagnose niacin deficiency.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    Different branches of tryptophan processing left a detectable blood pattern.
    primary_references
    [b6-dasilva2013] Metabolite profile analysis reveals functional effects of 28-day vitamin B-6 restriction on one-carbon metabolism and tryptophan catabolic pathways in healthy men and women (2013). https://pubmed.ncbi.nlm.nih.gov/23966327/ DOI: 10.3945/jn.113.180588
    tissue_or_cell_type
    Human blood and whole-body measurements
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1436–1447

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Twenty-three healthy adults; paired pre/postprandial LC-MS/MS metabolite profiling. · source_derived_draft · unverified_draft

    ### b6-restriction-kynurenine-profile 3-Hydroxykynurenine increased 39% fasting and 34% after meals; kynurenic acid decreased 22% and 20%, respectively. Condition category: nutrient_deficiency nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Different branches of tryptophan processing left a detectable blood pattern. organism: Homo sapiens tissue_or_cell_type: Human blood and whole-body measurements experimental_model: Twenty-three healthy adults; paired pre/postprandial LC-MS/MS metabolite profiling. limitations: Does not measure brain neurotransmitters, tissue NAD synthesis or diagnose niacin deficiency. exposure: 28 days below 0.35 mg/day B6. Related restriction research program; do not count paper totals as independent trial replications. cross_nutrient: B6-dependent kynurenine reactions intersect the tryptophan-to-niacin network; conversion to NAD was not measured. [b6-dasilva2013] Metabolite profile analysis reveals functional effects of 28-day vitamin B-6 restriction on one-carbon metabolism and tryptophan catabolic pathways in healthy men and women (2013). https://pubmed.ncbi.nlm.nih.gov/23966327/ DOI: 10.3945/jn.113.180588
    Complete structured claim and evidence

  2. Kynurenic-acid NMDA-blocking IC50 shifted from about 15 to 235 micromolar when 10 micromolar glycine was present.

    Glycine → Rat NMDA-type glutamate receptors, subunits unresolved source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Rat neuronal electrophysiological assay.
    limitations
    An assay co-agonist effect does not show that glycine supplements change human disease outcomes.
    nutrient_topic
    Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Tryptophan
    plain_language
    A second amino acid changed how strongly the metabolite blocked a receptor.
    primary_references
    The brain metabolite kynurenic acid inhibits alpha7 nicotinic receptor activity and increases non-alpha7 nicotinic receptor expression: physiopathological implications. · 2001 · https://pubmed.ncbi.nlm.nih.gov/11567036/ · DOI 10.1523/JNEUROSCI.21-19-07463.2001

    Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19) · lines 314–320

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Rat neuronal electrophysiological assay. · source_derived_draft · unverified_draft

    ## tryptophan-glycine-kyna-nmda A second amino acid changed how strongly the metabolite blocked a receptor. Kynurenic-acid NMDA-blocking IC50 shifted from about 15 to 235 micromolar when 10 micromolar glycine was present. Model: Rat neuronal electrophysiological assay. Limitations: An assay co-agonist effect does not show that glycine supplements change human disease outcomes. Evidence access: Primary abstract The brain metabolite kynurenic acid inhibits alpha7 nicotinic receptor activity and increases non-alpha7 nicotinic receptor expression: physiopathological implications. · 2001 · https://pubmed.ncbi.nlm.nih.gov/11567036/ · DOI 10.1523/JNEUROSCI.21-19-07463.2001
    Complete structured claim and evidence

  3. IL4I1 generated indole metabolites and kynurenic acid that activated AHR in the cancer study.

    Human interleukin-4-induced protein 1 / IL4I1 → Human aryl hydrocarbon receptor / AHR source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Human cancer/biochemical work with separate mouse CLL experiments.
    limitations
    This abstract groups several products; their individual concentrations and relative causal contributions are not resolved here.
    nutrient_topic
    Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Tryptophan
    plain_language
    Another enzyme can feed the same receptor through different metabolites.
    primary_references
    IL4I1 Is a Metabolic Immune Checkpoint that Activates the AHR and Promotes Tumor Progression. · 2020 · https://pubmed.ncbi.nlm.nih.gov/32818467/ · DOI 10.1016/j.cell.2020.07.038

    Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19) · lines 450–456

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human cancer/biochemical work with separate mouse CLL experiments. · source_derived_draft · unverified_draft

    ## tryptophan-il4i1-route Another enzyme can feed the same receptor through different metabolites. IL4I1 generated indole metabolites and kynurenic acid that activated AHR in the cancer study. Model: Human cancer/biochemical work with separate mouse CLL experiments. Limitations: This abstract groups several products; their individual concentrations and relative causal contributions are not resolved here. Evidence access: Primary abstract IL4I1 Is a Metabolic Immune Checkpoint that Activates the AHR and Promotes Tumor Progression. · 2020 · https://pubmed.ncbi.nlm.nih.gov/32818467/ · DOI 10.1016/j.cell.2020.07.038
    Complete structured claim and evidence

  4. Human KAT-II/AADAT is a PLP-dependent homodimer; the structure shows a PLP–Lys263 aldimine at its catalytic site.

    AADAT / KAT II → PLP source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Human KAT-II crystal structure at 1.83 angstrom resolution.
    limitations
    Cofactor dependence alone does not define clinical B6 requirements or benefit from excess B6.
    nutrient_topic
    Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Tryptophan
    plain_language
    Vitamin B6 participates in a branch enzyme, not only the serotonin route.
    primary_references
    Structure of the PLP-Form of the Human Kynurenine Aminotransferase II in a Novel Spacegroup at 1.83 Å Resolution. · 2016 · https://pubmed.ncbi.nlm.nih.gov/27023527/ · DOI 10.3390/ijms17040446

    Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19) · lines 202–208

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human KAT-II crystal structure at 1.83 angstrom resolution. · source_derived_draft · unverified_draft

    ## tryptophan-kat2-plp Vitamin B6 participates in a branch enzyme, not only the serotonin route. Human KAT-II/AADAT is a PLP-dependent homodimer; the structure shows a PLP–Lys263 aldimine at its catalytic site. Model: Human KAT-II crystal structure at 1.83 angstrom resolution. Limitations: Cofactor dependence alone does not define clinical B6 requirements or benefit from excess B6. Evidence access: Primary abstract Structure of the PLP-Form of the Human Kynurenine Aminotransferase II in a Novel Spacegroup at 1.83 Å Resolution. · 2016 · https://pubmed.ncbi.nlm.nih.gov/27023527/ · DOI 10.3390/ijms17040446
    Complete structured claim and evidence

  5. Muscle-specific PGC-1alpha1 transgenic mice resisted depression-like changes induced by chronic mild stress or kynurenine administration as peripheral kynurenine handling shifted.

    Mouse PGC-1alpha1 / Ppargc1a isoform 1 → Mouse stress/kynurenine-associated depression-like behavior source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Mouse genetic overexpression and behavioral challenges.
    limitations
    Not proof that this is the sole human exercise–mood mechanism or that kynurenic acid freely enters the brain.
    nutrient_topic
    Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Tryptophan
    plain_language
    A peripheral metabolic change altered a brain-related behavioral response.
    primary_references
    Skeletal muscle PGC-1α1 modulates kynurenine metabolism and mediates resilience to stress-induced depression. · 2014 · https://pubmed.ncbi.nlm.nih.gov/25259918/ · DOI 10.1016/j.cell.2014.07.051

    Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19) · lines 618–624

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Mouse genetic overexpression and behavioral challenges. · source_derived_draft · unverified_draft

    ## tryptophan-muscle-brain-context A peripheral metabolic change altered a brain-related behavioral response. Muscle-specific PGC-1alpha1 transgenic mice resisted depression-like changes induced by chronic mild stress or kynurenine administration as peripheral kynurenine handling shifted. Model: Mouse genetic overexpression and behavioral challenges. Limitations: Not proof that this is the sole human exercise–mood mechanism or that kynurenic acid freely enters the brain. Evidence access: Primary abstract Skeletal muscle PGC-1α1 modulates kynurenine metabolism and mediates resilience to stress-induced depression. · 2014 · https://pubmed.ncbi.nlm.nih.gov/25259918/ · DOI 10.1016/j.cell.2014.07.051
    Complete structured claim and evidence

  6. Carbidopa inhibition of kynurenine aminotransferase activity impaired aspartate synthesis and mitochondrial respiration and reduced mouse exercise performance and muscle force.

    Mouse skeletal-muscle kynurenine aminotransferases; multiple enzymes → Mouse muscle aspartate synthesis and mitochondrial respiration during kynurenine metabolism source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_access
    Primary abstract
    experimental_model
    Mouse muscle/exercise experiments within a PGC-1alpha1 and malate–aspartate-shuttle study.
    limitations
    Carbidopa is not specific to a single KAT isoform; mouse exposures do not establish the same effect at a clinical human dose.
    nutrient_topic
    Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Tryptophan
    plain_language
    The branch can support muscle energy handling as well as alter circulating metabolites.
    primary_references
    Skeletal muscle PGC-1α1 reroutes kynurenine metabolism to increase energy efficiency and fatigue-resistance. · 2019 · https://pubmed.ncbi.nlm.nih.gov/31235694/ · DOI 10.1038/s41467-019-10712-0
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19) · lines 626–632

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Mouse muscle/exercise experiments within a PGC-1alpha1 and malate–aspartate-shuttle study. · source_derived_draft · unverified_draft

    ## tryptophan-muscle-kat-inhibition The branch can support muscle energy handling as well as alter circulating metabolites. Carbidopa inhibition of kynurenine aminotransferase activity impaired aspartate synthesis and mitochondrial respiration and reduced mouse exercise performance and muscle force. Model: Mouse muscle/exercise experiments within a PGC-1alpha1 and malate–aspartate-shuttle study. Limitations: Carbidopa is not specific to a single KAT isoform; mouse exposures do not establish the same effect at a clinical human dose. Evidence access: Primary abstract Skeletal muscle PGC-1α1 reroutes kynurenine metabolism to increase energy efficiency and fatigue-resistance. · 2019 · https://pubmed.ncbi.nlm.nih.gov/31235694/ · DOI 10.1038/s41467-019-10712-0
    Complete structured claim and evidence

  7. The PGC-1alpha1–PPAR-alpha/delta program increased muscle kynurenine aminotransferases and conversion of kynurenine to kynurenic acid.

    Mouse PGC-1alpha1 / Ppargc1a isoform 1 → Mouse skeletal-muscle kynurenine aminotransferases; multiple enzymes source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Mouse skeletal-muscle transgenic and stress experiments.
    limitations
    Multiple aminotransferases are involved; do not assign the entire effect to human AADAT alone.
    nutrient_topic
    Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Tryptophan
    plain_language
    Muscle metabolism can change which tryptophan products remain in circulation.
    primary_references
    Skeletal muscle PGC-1α1 modulates kynurenine metabolism and mediates resilience to stress-induced depression. · 2014 · https://pubmed.ncbi.nlm.nih.gov/25259918/ · DOI 10.1016/j.cell.2014.07.051

    Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19) · lines 610–616

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Mouse skeletal-muscle transgenic and stress experiments. · source_derived_draft · unverified_draft

    ## tryptophan-muscle-kat-program Muscle metabolism can change which tryptophan products remain in circulation. The PGC-1alpha1–PPAR-alpha/delta program increased muscle kynurenine aminotransferases and conversion of kynurenine to kynurenic acid. Model: Mouse skeletal-muscle transgenic and stress experiments. Limitations: Multiple aminotransferases are involved; do not assign the entire effect to human AADAT alone. Evidence access: Primary abstract Skeletal muscle PGC-1α1 modulates kynurenine metabolism and mediates resilience to stress-induced depression. · 2014 · https://pubmed.ncbi.nlm.nih.gov/25259918/ · DOI 10.1016/j.cell.2014.07.051
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

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